That's a tough list and the LF games (particularly LF2) have been skyrocketing in price for the last few years. Spiker seems stable, if not cheaper than its peak. Mountain Madness is the cheapest and easiest to find, but might be tough to find in excellent condition.
I myself essentially gave up on LF2 and Spiker due to the prices and instead opted for the original carts only with reproduction boxes, manuals, and Flashback overlays. I paid just under $600 total for those two carts with the repro accessories. Comparing that to ~$2k for those two CIB, I just couldn't justify paying the extra $1400 for two boxes and low quality B&W paper manuals.
If you have any decent rare trade bait, you might be able to work out a deal with someone with extras. All that said, I wish you luck on your journey 👍